Cornus canadensis vs dogwood

Cornus canadensis and dogwood both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cornus canadensis	Yes	No	No	No
dogwood	Yes	No	No	No

As nouns, dogwood is a hypernym of Cornus canadensis; that is, dogwood is a word with a broader meaning than Cornus canadensis:

Cornus canadensis: creeping perennial herb distinguished by red berries and clustered leaf whorls at the tips of shoots; Greenland to Alaska
dogwood: a tree of shrub of the genus Cornus often having showy bracts resembling flowers

Other hypernyms of Cornus canadensis include cornel, dogwood tree.

Cornus canadensis (noun)	dogwood (noun)
creeping perennial herb distinguished by red berries and clustered leaf whorls at the tips of shoots; Greenland to Alaska	a tree of shrub of the genus Cornus often having showy bracts resembling flowers
	hard tough wood of any dogwood of the genus Cornus; resembles boxwood